The Federal Electoral Boundary Commission re-assesses ridings every decade following the census to reflect any changes in provincial demographics. Since 2001 populations has decreased in northern Ontario but increased significantly in southern Ontario.

The new ridings reflect those changes and parcel out new electoral areas in Toronto, Ottawa, Kitchener, Hamilton, Mississauga, Halton, Brampton, Simcoe, York, Belleville and Durham - some of which are traditional Tory strongholds.

Malcolm Allen, NDP MP for Welland, said he the commission did a "pretty good job" and added "a number of my colleagues went to open public meetings".

Meanwhile, two northern Ontario ridings remain the same after the commissioner found "inappropriate involvement" by the NDP MPs who represent them.

"The advice received at those public hearing, combined with the inappropriate involvement of at least two MPs persuaded the commission to conclude that the status quo, with a few minor boundary adjustments, is the best solution it can achieve for northern Ontario," the report says.

The Conservatives were quick to jump on those criticisms, issuing a statement saying: "These NDP members are hypocrites for their 'do as I say, not as I do' behaviour," and questioned whether Opposition Leader Thomas Mulcair "gave prior approval."

The complaint echoes recent NDP charges that the Conservatives interfered in Saskatchewan's boundary review by making anonymous robocalls to generate opposition to proposed changes.

The NDP accused the Tories of opposing changes because they stood to lose seats, not because changes were unnecessary, as the Conservatives argued in the House.

New electoral districts in Tory territory

The Federal Electoral Boundary Commission re-assesses ridings every decade following the census to reflect any changes in provincial demographics. Since 2001 populations has decreased in northern Ontario but increased significantly in southern Ontario.

The new ridings reflect those changes and parcel out new electoral areas in Toronto, Ottawa, Kitchener, Hamilton, Mississauga, Halton, Brampton, Simcoe, York, Belleville and Durham - some of which are traditional Tory strongholds.